Variable speed drive



FIG. 1 is a front, top, and right side perspective view of a variable speed drive;

FIG. 2 is a front, bottom, and left side perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a left side elevational view thereof; and,

FIG. 5 is a rear, bottom, and right side perspective view thereof.

The broken lines in the drawings illustrate environmental subject matter and form no part of the claimed design. 

CLAIM The ornamental design for a variable speed drive, as shown and described. 